Spring units

ABSTRACT

A spring unit ( 2 ) for incorporation into a bed, divan bed, mattress, or other upholstery unit comprises a first spring ( 4 ) and a second spring located ( 6 ) within said first spring ( 4 ). The first spring ( 4 ) may be a pocketted spring, or the second spring may be a pocketted spring, or both of said springs may be pocketted springs, the pockets of said pocketted springs being composed of a woven material and/or a synthetic material.

[0001] This invention relates to spring units and more particularly tospring units for beds, divan beds, mattresses, and other upholsteryunits. Such beds etc will be hereinafter referred to as ‘sprung units’.

[0002] Sprung units are conventionally made in differing degrees ofhardness, this usually being achieved by varying the number of springsper unit area—generally known as ‘the spring count’—of the sprung unit,or by changing the gauge of the wire from which the springs are made.Such variation in the manufacturing procedure, i.e. the incorporation ofdiffering numbers of springs or changing the wire gauge, complicates themanufacturing procedure and consequently increases the manufacturingcosts.

[0003] It has previously been proposed to incorporate a second springwithin a first spring so as to form a double spring unit whereby thesprings are compressed in stages so as to lessen the shock on the sprungunit when a person sits or lays upon the sprung unit, Examples of suchspring units are shown and described in U.S. Pat. Nos. 1,192,510(Fischmann), 3,031,690 (Ramsey), and 2,631,840 (Bugenhagen). However, insuch previous proposals, the second spring has been connected, eitherdirectly or indirectly, to said first spring such that the second springhas not been freely movable within said first spring, which placesrestrictions on the sprung unit in use.

[0004] The present invention therefore seeks to provide an improved formof spring unit which will obviate the disadvantages of known springunits.

[0005] According to the present invention there is provided a springunit for incorporation into a bed, divan bed, mattress, or otherupholstery unit comprising a first spring and a second spring locatedwithin said first spring, said second spring having no connection tosaid first spring so as to be freely movable within said first spring.

[0006] Preferably, the length of said second spring will be less thanthat of said first spring.

[0007] In an embodiment of the invention, the first spring may be apocketted spring, and in an alternative embodiment of the invention thesecond spring may be a pocketted spring. In yet a further alternativeembodiment, each of said first and second springs may be pockettedsprings.

[0008] The pocket of the or each pocketted spring may be composed of awoven material such as calico which is sewn in order to form thepocket(s). Alternatively, the pocket(s) may be composed of syntheticmaterial which is sewn or sonic or heat welded in order to form thepocket(s). Where both springs are pocketted springs, both pockets may becomposed of a woven material or both may be composed of syntheticmaterial, or the pockets may be formed one of each material, the pocketof woven material preferably being around said first spring.

[0009] According to another aspect of the present invention there isprovided a sprung unit incorporating a plurality of spring units, eachof said spring units comprising a first spring and a second springlocated within said first spring.

[0010] In order that the invention may be more readily understood,embodiments of the invention will now be described, by way of exampleonly, reference being made to the accompanying drawings, wherein:

[0011]FIG. 1 is a view of a spring unit according to a first embodimentof the invention;

[0012]FIG. 2 is a view of a spring unit according to a second embodimentof the invention;

[0013]FIG. 3 is a view of a spring unit according to a third embodimentof the invention;

[0014]FIG. 4 is a view of a further embodiment of a spring unitaccording to the invention; and

[0015]FIG. 5 is a view of a sprung unit, partly cut away, to show theincorporation of a plurality of spring units.

[0016] Referring to the drawings and firstly to FIG. 1, there is shown aspring unit which is indicated generally by reference numeral 2 andwhich comprises a first, outer spring 4 and a second, inner spring 6. Aswill be seen, the length of the inner spring is less than the length ofthe outer spring 4, and the pitch of the spring 6 is less than that ofthe spring 4.

[0017] The inner spring 6, captive within the outer spring 4, is movablelongitudinally within the outer spring 4 between the end 4A and theother end 4B of the spring 4.

[0018] Referring now to FIG. 2, it will be seen that the outer spring 4and the inner spring 6 are located within a single pocket 8—so as toform a pocketted spring A—in engagement with the outer spring 4. Thepocket is formed by longitudinal lines of retention 10 and 12 and bylateral lines of retention 14 and 16.

[0019] The pocket 8 may be composed of a woven material such as calico,in which case the lines of retention will be formed by sewing.Alternatively, the pocket 8 may be composed of a synthetic material, inwhich case the lines of retention may be formed either by sewing or bymeans of sonic or heat welding.

[0020] As with the spring unit of FIG. 1, the inner spring 6 is movablewithin the pocket 8 of the outer spring 4.

[0021]FIG. 3 illustrates a spring unit 2 in which the inner spring 6 islocated within a pocket 20—so as to form a pocketted spring B—which iscomposed of either a woven material such as calico, in which case thepocket will be secured in position around the spring 6 by sewing, oralternatively of synthetic material, in which case the pocket 20 will besecured in position around the spring 6 either by sewing or by sonic orheat welding. The pocketted spring B, formed by the pocket 20 and thespring 6, is as in the embodiment of FIGS. 1 and 2, movablelongitudinally between the end 4A and the end 4B of the outer spring 4.

[0022] Referring now to FIG. 4, there is illustrated a ‘composite’pocketted spring unit which is a combination of the spring units ofFIGS. 2 and 3. Thus the spring unit of FIG. 4 comprises an outerpocketted spring A and an inner pocketted spring B, and for ease ofidentification, the reference numerals of FIGS. 2 and 3 have beenapplied to FIG. 4. The inner pocketted spring B is movablelongitudinally within the outer pocketted spring A from one end 4A tothe other end 4B of the outer pocketted spring A.

[0023] The pockets of the pocketted springs A and B may both be composedof a woven material such as calico, or both may may be composed of asynthetic material, or there may be one of each, in which case it ispreferred that the pocket of pocketted spring A is composed of the wovenmaterial.

[0024] In use, and referring to now to FIG. 5, which illustrates part ofsprung unit 22, it will be seen that the unit incorporates aplurality—two are indicated—of the spring units as shown in FIG. 4, i.e.the composite pocketted spring unit. The spring units 2 are locatedbetween upper and lower layers of padding 24 and 26 and side walls 28and 30, the spring units being held in position in conventional manner.

[0025] The sprung unit 22 may be formed wholly of spring units inaccordance with the invention, or alternatively a plurality of springunits in accordance with the invention may be used in conjunction withor in combination with a plurality of conventional pocketted springs, orindeed with other suitable types of conventional and known springs.

[0026] Thus the invention provides a spring unit 2 and a sprung unit 22which incorporates a plurality of said spring units 2 wherein, in use ofthe sprung unit 22, the outer spring 4 will be partially compressedfirst followed by compression together of the outer spring 4 and theinner spring 6, the amount of compression of the spring(s) beingdependent upon the weight of the user.

[0027] Thus there is provided a sprung unit, i.e. a bed, divan bed,mattress or other upholstery unit, whose degree of hardness isvariable—depending upon the amount of compression of the springs of thesprung unit—and therefore it will not be necessary to manufacture ‘hard’sprung units and ‘soft’ sprung units by varying the ‘spring count’ ofthe unit, such ‘spring count’ automatically being adjusted andestablished by the user of the sprung unit.

[0028] Finally, it will be appreciated that whilst parallel springs andspring units have been described and illustrated, the invention isequally applicable to barrel shaped and other shaped springs and springunits.

1. A spring unit (2) for incorporation into a bed, divan bed, mattressor other upholstery unit comprising a first spring (4) and a secondspring (6) located within said first spring (4), characterised in thatsaid second spring (6) has no connection to said first spring (4) so asto be freely movable within said first spring (4).
 2. A spring unitaccording to claim 1, characterised in that the length of said secondspring (6) is less than that of said first spring (4).
 3. A spring unitaccording to claim 1 or claim 2, characterised in that said first spring(4) is a pocketted spring (A).
 4. A spring unit according to any ofclaims 1 to 3, characterised in that said second spring (6) is apocketted spring (13).
 5. A spring unit according to claim 3 or claim 4,characterised in that said pocketted spring (A) and said pockettedspring (B) each comprises a spring (4,6) located within a pocket (8,20)of woven material or synthetic material.
 6. A spring unit according toclaim 5, characterised in that said pockets (8,20) of woven material orsynthetic material are formed by sewing, heat welding or sonic welding.7. A bed, divan bed mattress, or other upholstery unit incorporating aplurality of spring units according to any of claims 1 to
 6. 8. A bed,divan bed, mattress, or other upholstery unit incorporating a pluralityof spring units each comprising a first pocketted spring (A) and asecond pocketted spring (B) located within said first pocketted spring(A), characterised in that said second pocketted spring (B) has noconnection to said first pocketted spring (A) so as to be freely movablewithin said first pocketted spring (A).